Exercise step using spirally shaped air-cushioning legs

ABSTRACT

Disclosed are embodiments of an exercise step that utilize spirally shaped air-cushioning legs. The direction of the spiral of the air-cushioning legs is alternated around the periphery of the exercise step to eliminate rotational creep. Flow regulators are utilized to control the flow of air from the top of each of the air-cushioning legs into an interior portion of the base of the exercise step. Spokes provide an air flow passage between the air flow regulators and the central air regulator, as well as providing structural support for the base. Rings are also used around the base that inner connect the spokes and provide additional support. Recessed portions of a lower plate of the base are welded to an upper plate during a blow molding process to add additional support to the base of the exercise step.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional application of U.S. patentapplication Ser. No. 13/241,604, filed Sep. 23, 2011, by Darrell A.Kulzer, entitled “EXERCISE STEP USING SPIRALLY SHAPED AIR-CUSHIONINGLEGS,” which application claims the benefit of U.S. ProvisionalApplication Ser. No. 61/392,409, filed Oct. 12, 2010, by Darrell A.Kulzer, entitled “EXERCISE STEP USING SPIRALLY SHAPED AIR-CUSHIONINGLEGS,” the disclosures of which are hereby incorporated herein byreference for all that they disclose and teach.

BACKGROUND

Exercise steps are a useful tool for physical conditioning. For example,exercise steps are used in step aerobic classes to increase aerobicactivity of participants. Users can participate in step aerobic classesin health clubs, exercise clubs and individually while watchingtelevision or videos. Step aerobics not only increase aerobic activityof the participants, but are also useful in burning calories and weightreduction. Heart rates of participants can be increased by stepping onand off of the exercise step, which frequently results in improvedphysical conditioning of the participant. As a result, the popularity ofexercise steps has increased since exercise steps provide a useful andconvenient way to improve physical conditioning.

SUMMARY

An embodiment of the present invention may further comprise method ofmaking an exercise step comprising: forming a plurality of clockwiseair-cushioning legs comprising: forming a first sidewall having aclockwise spirally shaped bulge that allows the clockwise air-cushioningleg to compress when a user steps onto the exercise step; attaching afirst non-slip cover to a bottom portion of the first sidewall to forman airtight seal with the bottom portion of the first sidewall; forminga first attachment plate that is connected to an upper portion of thefirst sidewall having latches for attaching the clockwise air-cushioninglegs to the exercise step; forming a plurality of counterclockwiseair-cushioning legs comprising: forming a second sidewall having acounterclockwise spirally shaped bulge that allows the counterclockwiseair-cushioning leg to compress when a user steps onto the exercise step;attaching a second non-slip cover to a bottom portion of the secondsidewall to form an airtight seal with the bottom portion of the secondsidewall; forming a second attachment plate that is connected to anupper portion of the second sidewall having latches for attaching thecounterclockwise air-cushioning legs to the exercise step; forming abase comprising: forming an upper plate from a parison in a blow moldingprocess; forming a lower plate from the parison in the flow moldingprocess comprising: forming a plurality of curved rings in the lowerplate that provide circumferential support to the lower plate; forming aplurality of spokes in the lower plate that inter-connect the pluralityof curved rings to provide lateral support to the lower plate, theplurality of spokes also providing a plurality of air flow passages;forming leg attachments in the lower plate that allow the latches on thefirst attachment plate and the second attachment plate to connect theair-cushioning legs to the lower plate with a substantially airtightseal; placing adjustable flow regulators on a first set of openings inthe leg attachments that allow air in the clockwise air-cushioning legsand the counterclockwise air-cushioning legs, that is compressed whenthe user steps onto the exercise step, to be individually and separatelycontrolled from the clockwise and counterclockwise air cushioning legsthrough the first set of openings in the leg attachments; placing an aircontrol regulator in the lower plate that is communicatively coupled tothe air flow passages that collectively controls air flow from the airflow passages; welding recessed portions of the lower plate to the upperplate to strengthen and form the air passages in the spokes; regulatingair flow in the first set of openings and the second opening to controlthe rate of flow of the compressed air from the clockwise air-cushioninglegs and the counterclockwise air-cushioning legs using the adjustableflow regulators and the air control regulator.

An embodiment of the invention may further comprise method of forming aspirally shaped air-cushioning leg comprising: providing an exteriormold having a spirally shaped leg portion for injection molding of theair-cushioning leg having a spiral shape; providing an interior moldthat has a spiral shape; injecting a thermoplastic material between theexterior mold and the interior mold in an injection molding device toform an air-cushioning leg molded piece; unscrewing the interior moldfrom the air-cushioning leg molded piece formed between the exteriormold and the interior mold after the air-cushioning leg molded piece hascooled sufficiently to allow the interior mold to be removed; releasingthe exterior mold to remove the spirally shaped air-cushioning leg.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, perspective view of one embodiment of a roundexercise step.

FIG. 2 is a top view of the embodiment of FIG. 1.

FIG. 3 is a bottom view of the base of the exercise step 100 illustratedin FIG. 1

FIG. 4 is a schematic, perspective view of another embodiment of an ovalshaped exercise step.

FIG. 5 is a top view of the embodiment of FIG. 4.

FIG. 6 is a bottom view of the base of the exercise step of FIG. 4.

FIG. 7 is a schematic, perspective view of another embodiment of an ovalexercise step.

FIG. 8 is a schematic top view of the embodiment of FIG. 7.

FIG. 9 is a schematic bottom view of the base of the exercise step ofFIG. 7.

FIG. 10 is a schematic, perspective view of a clockwise spiralair-cushioning leg.

FIG. 11 is a side view of the embodiment of FIG. 10.

FIG. 12 is a side view of an embodiment of a counterclockwise spiralair-cushioning leg.

FIG. 13 is a schematic side cutaway view of an embodiment of a blow moldfor forming the base of an exercise step illustrated in an openposition.

FIG. 14 is a schematic illustration of the embodiment of the blow moldof FIG. 13 in a closed position.

FIG. 15 is a schematic cutaway view of another embodiment of a blowmold.

FIG. 16 is a schematic illustration of the blow mold of FIG. 15 in aclosed position.

FIG. 17 is a sectional view of an injection mold for an air-cushioningleg.

FIG. 18 is a schematic perspective view of a flow regulator.

FIG. 19 is a schematic diagram of an embodiment of an air controlregulator.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is a schematic perspective view of an embodiment of a roundexercise step 100. As illustrated in FIG. 1, base 102 has an upper plate130, a lower plate 132 and a sidewall 118 that forms a lip 116 with theupper plate 130. The lip 116 is formed as a result of the upper plate130 being recessed from the sidewall 118. The top surface 114 can be alayer of rubberized material that provides a friction surface so thatusers do not slip when stepping onto the top surface 114 of the exercisestep 100. A layer of rubberized material also provides additionalcushioning. When a layer of material is used as top surface 114, a flushsurface is created with lip 116. Alternatively, the lip 116 can beeliminated and the upper plate 130 can be formed with a non-slipsurface, such as a grating or other friction surface, to prevent usersfrom slipping on the exercise step 100.

As also illustrated in FIG. 1, five air-cushioning legs aresubstantially evenly disposed around peripheral portions of the exercisestep 100. Legs 104, 106, 108, 110, 112 are attached to the lower plate132 in a manner that allows the legs 104-112 to be easily attached to,and removed from, the exercise step 100. Legs 104-112 can be removablyattached and sealed to lower plate 132 to provide an airtight sealbetween the bottom plate 132 and the air-cushioning legs 104-112. Legs104-112 are spirally shaped air-cushioning legs that compress when theuser steps on the exercise step 100. Air-cushioning legs 104-112 providecushioning for the user, to reduce stress on the knees, hips and back ofthe user of the exercise step 100 when stepping onto the exercise step100. The air-cushioning legs 104-112 are spirally shaped and, as such,only have a single cushioning bulge that spirally progresses around thecircumference of each of the legs 104-112. As shown in FIG. 1, thedirection of the spiral is different for each of the adjacent legs,which reduces any rotary creeping of the exercise step 100, as disclosedin more detail below.

FIG. 2 is a top view of the embodiment of the round exercise step 100,illustrated in FIG. 1. As shown in FIG. 2, a cutaway portion of the topsurface 114 is illustrated so that leg attachments and legs of theexercise steps 100 are illustrated. For example, legs 104, 106, 108,110, 112 are shown as being substantially evenly spaced around theperiphery of the exercise step 100. Each of the legs 104-112 is attachedto the exercise step 100 by the leg attachments 120, 122, 124, 126, 128.The lip 116 provides an edge on the sidewall 118, so that the topsurface 114 is flush with the sidewall 118. If a non-slip surface isformed in the top surface 114, a lip may not be included on sidewall118. The round configuration illustrated in FIG. 2 allows the exercisestep 100 to be constructed in a manner which provides strength, whileminimizing the amount of plastic material used in the exercise step 100,as explained in more detail with respect to FIG. 3.

FIG. 3 is a bottom view of the base 102 of the embodiment of theexercise step 100, illustrated in FIGS. 1 and 2. Base 102 includes thelower plate 132 that has a unique structural design that providesstrength to the exercise step 100. For example, an outer ring 136surrounds an inner ring 138, which provide structural support in acircumferential manner around the lower plate 132. In addition, theouter ridge 134 provides additional structural support around theperiphery of the lower plate 132. Long spokes 140, 142, 144, 146, 148connect the inner ring 138 to the center ring 160 to provide supportbetween the center ring 160, the inner ring 138 and the leg attachments120, 122, 124, 126, 128. Short spokes 150, 152, 154, 156, 158 connectthe outer ring 136 to the inner ring 138 and provide support between theouter ring 136 and the inner ring 138. Various small attachment spokes,such as small attachment spokes 162, 164, provide additional supportbetween the various rings and between the outer ring 136 and outer ridge134. Recessed portions are formed in-between the rings and spokes, suchas recessed portion 166. As explained in more detail below, the recessedportions are welded to the upper plate 130 during the blow moldingprocess of forming the exercise step 100.

FIG. 3 also illustrates a series of flow regulators 168, 170, 172, 174,176 that are disposed centrally in each of the leg attachments 120, 122,124, 126, 128, respectively. The flow regulators 168-176 may simplycomprise an opening that has a predetermined size to control the amountof air that flows from the air-cushioning legs 104-112 and the lowerplate 132 or may comprise an adjustable valve. Further, the flowregulator may comprise a porous material that allows air to flow throughan opening in the lower plate 132. In that regard, different porousmaterials can be used to adjust the amount of air flow through the flowregulators 168-176 by changing the porosity of the material. Forexample, foam-type material can be used, such as a foam rubber or a foamplastic material, which controls the amount of air flowing through theopening and also assists in reducing noise, such as whistling or othernoises that may be created by the flow of air through the opening. Legs104-112 can be constructed so that an airtight seal is created betweenan open portion of the upper part of each of the legs 104-112 and eachof the leg attachments 120-128 on lower plate 132. Alternatively, or inaddition to the flow regulators 168-176, a central air control regulator178 can be placed in the center ring 160. The central air controlregulator 178 can comprise an adjustable control valve to adjust thesize of the opening of the central air control regulator 178.Alternatively, central air control regulator 178 may comprise an openingwith a porous material disposed in the opening that controls the flow ofair through the central air control regulator 178. Again, differenttypes of porous materials can be used to control the amount of flow ofair. Porous material can be mounted in a ring that snap fits into thecenter ring 160, or mounted in any desired manner, so that the centralair control regulator 178 can be installed and removed easily by a user.The long spokes 140-148 provide an air passage for flow of air betweenflow regulators 168-176 and central air control regulator 178. Longspokes 140-148 provide a dual function of providing both a supportstructure for the lower plate 132 and an air channel between the legattachments 120-128 and the center ring 160.

FIG. 4 is an illustration of another embodiment of an exercise step 400.Exercise step 400 is an oval-shaped exercise step that has four legs412, 414, 416, 418. Each adjacent leg of the legs 412-418 has anoppositely oriented spiral. For example, leg 412 has a counterclockwisespiral, while leg 414 has a clockwise spiral. Leg 416 has acounterclockwise spiral and leg 418 has a clockwise spiral. Thedifferent directions of the spiral prevent any rotational creep of theexercise step 400 when the exercise step 400 is repeatedly stepped onand repeatedly compressed.

The exercise step 400, illustrated in FIG. 4, has a base 402 and a topsurface 427 that is attached to the base 402. Top surface 427 provides anon-slip surface, which can either be a separate layer of material thatis attached to the base 402, or can be a non-slip surface formed in theupper plate 406 of the base 402. The upper plate 406 is attached to thelower plate 408 and forms a sidewall 410 that provides structuralsupport for the base 402. The upper and lower plates are attached duringa blow molding process disclosed below with respect to FIGS. 13 and 14.The sidewall 410 forms an optional lip 404. When a separate top surfacelayer 427 is attached to the upper plate 406, the lip 404 is flush withthe top surface 427. Legs 412-418 are attached to the lower plate 408 byway of leg attachments 420, 422, 424, 426, respectively.

FIG. 5 is a top view of the oval-shaped exercise step 400 illustrated inFIG. 4. As illustrated in FIG. 5, legs 412-418 are spaced around theexercise step 400 to provide secure support to the exercise step 400.The legs 412-418 are attached to the exercise step 400 via the legattachments 420, 422, 424, 426, respectively. A top surface 427 providesa non-slip surface on the top of the exercise step 400. The optional lip404 provides a flush surface between the top surface 427 and the edge ofthe exercise step 400 to prevent tripping by the user and damage to topsurface 427.

FIG. 6 is a bottom view of the base 402 of the exercise step 400 ofFIGS. 4 and 5, illustrating the structure of the lower plate 408. Lowerplate 408 is similar to the lower plate 132 illustrated in FIG. 3, withthe exception that lower plate 408 is shaped in an oval pattern. The legattachments 420-426 are formed in the lower plate 408 and provide anairtight seal between the lower plate 408 and the air-cushioning legs412-418. Flow regulators 456, 458, 460, 462, allow air that iscompressed, as a result of the compression of the air-cushioning legs412-418 during use, to flow through the flow regulators 456-462. Thecompressed air flows through the long spokes 442, 444, 446, 448 to thecenter ring 452 and out of the base 402 via central air controlregulator 464. Flow regulators 456-462 and central air control regulator464 can comprise the same types of valves as described with respect toFIG. 3. Again, structural support is provided to the base 402 by theseries of long spokes 442-448, short spokes 432, 434, 436, 438, innerring 430, outer ring 428, and center ring 452. In addition, varioussmall spokes are used in the same manner as utilized in FIG. 3 toprovide additional support. Long spokes 442-448 provide a dual functionof providing both a support structure for the lower plate 408 and an airchannel between the leg attachments 420-426 and the center ring 452.

FIG. 7 is a schematic perspective view of another embodiment of anexercise step 700. As illustrated in FIG. 7, base 702 has an oval shapethat is different from the oval shape illustrated in FIGS. 3-6. Exercisestep 700 has four legs 712, 714, 716, 718 that are attached to the lowerplate 706 of base 702. Sidewall 708 provides a continuous surfacebetween the upper plate 704 and lower plate 706, which providesadditional support to the base 702. Sidewall 708 forms a lip 710 thatextends upwardly from the level of the upper plate 704. Top surface 728can be a separate layer of material that is attached to the upper plate704 to provide a non-slip surface for the exercise step 700. Lip 710provides a flush surface between the top portion of the top surface 728and the sidewall 708. As also illustrated in FIG. 7, leg attachments720, 722, 724, 726 are disposed on the lower plate 706 so that the legs712-718 can be attached to the lower plate 706 with an airtight seal.The legs 712-718 are air-cushioning legs that compress when a user stepsonto the exercise step 700. The air-cushioning is provided by a singlespiral bulge that forms the sidewall of the air-cushioning leg, asdisclosed in more detail below.

FIG. 8 is a top view of the oval-shaped exercise step 700 of FIG. 7. Asillustrated in FIG. 8, legs 712-718 are spaced around the periphery ofthe base 702 of the exercise step 700. The top surface 728 is a non-slipsurface that can be constructed of a separate material, such as acushioning material, to further add cushioning to the exercise step 700.As indicated above, the lip 710 provides a flush surface between the top728 and the sidewall 708. Alternatively, the upper plate 704 can beformed with a non-slip surface, so as to eliminate a separate layer. Legattachments 720, 722, 724, 726 are disposed in the lower plate andprovide a latching mechanism to latch the legs 712-718 to the lowerplate 706.

FIG. 9 is a bottom view of the lower plate 706 of the exercise step 700,illustrated in FIGS. 7 and 8. As illustrated in FIG. 9, the lower plate706 has a plurality of spokes 730 that provides longitudinal support tothe lower plate 706. In addition, rings 732, 734 provide circumferentialsupport for the lower plate 706. The combination of the spokes 730 andrings 732-736 provide support for the lower plate 706, so that theamount of plastic material disposed in the lower plate 706 can bereduced. The reduction in the amount of plastic material in the lowerplate 706 provides a great deal of savings in the construction of theexercise stool 700.

As also illustrated in FIG. 9, leg attachments 720, 722, 724, 726 aredisposed in the lower plate 706. Flow regulators 738, 740, 742, 744 cansimply comprise an opening in the lower plate 706, or a regulator ofsome type can be disposed in the opening. For example, a porous materialmay be placed in the openings of the flow regulators 738-744 to controlthe flow of air, as well as limit sounds created by the flow of air,such as whistling. Each of the flow regulators 738-744 are connected tothe center ring 746 via spokes 730. Again, spokes 730 provide a dualfunction of providing both a support structure for the lower plate 706and an air channel between the leg attachments 720-726 and the centerring 746. Center ring 746 includes a central air control regulator 748that regulates the flow of air from the interior portion of the base 702to the external environment. The central air control regulator 748 maycomprise a control valve, a specially sized opening, or may include anopening with a porous material disposed in the opening that controls theamount of flow of air through the opening of the central air controlregulator, as disclosed in more detail below.

FIG. 10 is a schematic perspective view of a clockwise spiral leg 1000.As shown in FIG. 10, the clockwise spiral leg 1000 has a spiral body1002 that comprises a single bulge that forms the sidewall of theclockwise spiral leg 1000, which has a spiral twist in a clockwisedirection. A non-slip cover 1006 is attached to the lower portion of thespiral body 1002. Non-slip cover 1006 is intended to provide a non-slipsurface for the clockwise spiral leg 1000. An attachment plate 1004 isconnected to an upper portion of the spiral body 1002 of the clockwisespiral leg 1000. Latching flanges 1008, 1010 provide a latchingmechanism for latching to the leg attachments on the bottom plate of theexercise stool.

The clockwise spiral leg 1000, that is illustrated in FIG. 10, can beconstructed using injection molding techniques. The advantage of using aspiral body 1002 is that an inner rotating mold that is used in theformation of the spiral body 1002 can be removed by rotating the innerrotating mold to unscrew the inner rotating mold from the spiral body1002, as disclosed in more detail below with respect to FIG. 17. The useof a spiral inner rotating mold simplifies the injection molding processand allows the air-cushioning legs to be quickly and easily constructed.The air-cushioning provided by the spiral body 1002 reduces the amountof plastic material required to support and cushion the exercise steps100, 400 and 700.

FIG. 11 is a side view of the clockwise spiral leg 1000. As shown inFIG. 11, the clockwise spiral leg 1000 has a spiral body or sidewall1002 that forms a primary structural component of the clockwise spiralleg 1000. The spiral body or sidewall 1002 has a thickness and is madefrom a material that allows the spiral body 1002 to compress when a usersteps on the exercise step. The spiral bulge is a single bulge thatflexes outwardly to allow the spiral body 1002 to compress. As indicatedabove, the compression of the spiral body 1002 may cause a slightrotational creeping of the exercise step. For that reason, and asdisclosed above, the clockwise and counterclockwise spiral legs areattached to the lower plate in an alternating configuration to offsetrotational creep. The non-slip cover 1006 provides an airtight seal tothe bottom of the spiral body 1002 and provides a non-slip surface thatreduces skidding of the clockwise spiral leg 1000. Attachment plate 1004is formed together with the spiral body 1002 and provides an attachmentsurface for the clockwise spiral leg 1000 to the base 102 of theexercise step 100, as illustrated in FIG. 1, and other embodimentsdisclosed herein. Latching hinge 1008 is adapted to latch to the legattachments, such as leg attachments 120-128, illustrated in FIG. 1, andprovide a substantially airtight seal between the interior of theclockwise spiral leg 1000 and the base of the exercise step, such asbase 102 of exercise step 100, as well as the other embodimentsdisclosed herein.

FIG. 12 is a side view of a counterclockwise spiral leg 1200. As shownin FIG. 12, the spiral body 1202 has a counterclockwise rotation thatdiffers from the clockwise rotation of the spiral body 1002 illustratedin FIGS. 10 and 11. The counterclockwise spiral leg 1200 is otherwisethe same as the clockwise spiral leg 1000. For example, nonskid cover1206 is connected to the bottom portion of the spiral leg 1202 andprovides an airtight seal along the bottom portion of the spiral body1202. The attachment plate 1204 is formed together with the spiral body1202, as well as latching flange 1208. The attachment plate 1204 forms asubstantially airtight seal with the leg attachments of the base of theexercise step when the latching flange 1208 secures the counterclockwisespiral leg 1200 to the base of the exercise step.

FIGS. 13 and 14 show partial cutaway views of one embodiment of a blowmolding apparatus 1300 for forming the base for the exercise step, suchas base 102 of exercise step 100, as illustrated in FIG. 1, and otherembodiments disclosed herein. As shown in FIG. 13, an extruder head 1302extrudes melted plastic 1304 through openings 1306, 1308 to form parison1322. Air compressor 1310 generates compressed air, which is applied toa control valve 1312 via air tube 1314. Air tube 1316 allows air to beinserted in to the interior portion of parison 1322. Control valve 1312controls the inflation of the parison 1322. Moveable molding plates1318, 1320 provide a blow molding cavity for the parison 1322. Moveablemolding plate 1320 has a flat surface 1332 that corresponds to the flatsurface that is created for the upper plate of the exercise step, suchas upper plate 130 of exercise step 100, illustrated in FIG. 1, andother embodiments disclosed herein. Indentation 1334 corresponds to alip that is formed adjacent to the upper plate, such as lip 116 that isadjacent to upper plate 130, as shown in FIG. 1 and other embodimentsdisclosed herein. Moveable molding plate 1318 has a series ofindentations, such as indentation 1324, as well as a series ofprotrusions, such as protrusion 1326. The moveable molding plate 1318 isdriven inwardly toward moveable molding plate 1320 by way of pistoncontroller 1330 and piston 1328. Similarly, moveable molding plate 1320is driven inwardly by piston controller 1338 and piston 1336. As themoveable molding plates 1318, 1320 are driven inwardly, the parison 1322is pushed inwardly to create a molded piece.

FIG. 14 is a schematic cutaway view of the blow mold of FIG. 13 in aclosed position. As shown in FIG. 14, the parison 1322 conforms to thesurface of the moveable molding plates 1318, 1320. The protrusions inmoveable molding plate 1318, such as protrusion 1326, push the parison1322 inwardly until plastic welds are formed between each of theinterior sides of the parison 1322, such as plastic weld 1340, adjacentto the protrusions, such as protrusion 1326. The plastic welds that arecreated between the interior opposing sides of the parison 1322, such asplastic weld 1340, provide structural strength and integrity to themolded piece that forms the base of the exercise step. In addition, thevarious rings and spokes that are created by the alternating protrusionsand indentations in moveable plate 1318, also provide additionalstructural rigidity to the lower plate, such as lower plate 131,illustrated in FIG. 1, as well as the other lower plates in the otherembodiments disclosed herein. The additional structural rigidity andstrength of the base, such as base 102 of exercise step 100, as well asthe other embodiments disclosed herein, allow the amount of plasticmaterial utilized in the base, such as base 102, to be reduced. Theexpense of the plastic materials used to form the molded pieces can be asignificant portion of the expense of the overall cost of the exercisestep. Hence, reduction in the amount of plastic material, whileproviding adequate structural support, can result in significant costsavings. For purposes of simplicity, one of the moveable plates 1318,1320, can be fixed and non-moveable, while the other moveable moldingplate can be moved to compress the parison 1322 in the mannerillustrated in FIG. 14. Hence, one set of piston controllers 1330, 1338and one set of pistons 1328, 1336 can be removed to reduce the cost ofthe blow mold 1300.

FIG. 15 is a schematic cutaway view of another embodiment of a blow mold1500. As illustrated in FIG. 15, the blow mold 1500 includes an extruder1502 that extrudes the melted plastic 1504 to form a parison 1522. Themelted plastic 1504 is extruded through openings 1506, 1508 and enteredinto a molding cavity through an opening, which is centrally located inmolding plate 1518. Air compressor 1510 generates a supply of compressedair, which is applied to control valve 1512 via air tube 1514. Controlvalve 1512 controls the pressure that is applied to the parison via airsupply 1516. Molding plate 1518 includes a series of protrusions, suchas protrusion 1526 and a plurality of indentations, such as indentation1524. Molding plate 1518 molds the lower plate of the exercise step.Moveable molding plate 1520 has a flat surface 1528 that corresponds tothe flat upper surface of the upper plate of the exercise step, such asupper plate 130 of exercise step 100 of FIG. 1, and other upper platesof other embodiments disclosed herein. Indentation 1536 creates a lip inthe upper plate, such as lip 116, illustrated in FIG. 1, and lips onother embodiments disclosed herein. Molding plate 1518 can either be amoveable plate, or can be fixed. Similarly, moveable molding plate 1520can be moved by pistons 1530, 1532, 1534, which are attached to a pistoncontroller 1538. Piston controller 1538 controls the movement ofmoveable molding plate 1520 to squeeze or compress the parison 1522.

FIG. 16 is a schematic illustration of the blow mold 1500 in a closedposition. As shown in FIG. 15, piston controller 1538 has extended thepistons 1530, 1532, 1534 to move the moveable molding plate 1520 towardsthe molding plate 1518. The air compressor 1510 supplies compressed airto the control valve 1512 that ensures that the proper inflation of theparison 1522 has occurred, so that the parison 1522 expands to thesurfaces of both the molding plate 1518 and the moveable molding plate1520 in the closed position, as shown in FIG. 16. A plurality of plasticwelds are created between the opposing inner surfaces of the parison1522 adjacent to the protrusions in the molding plate 1518, such asprotrusion 1526. The indentations, such as indentation 1524, maycomprise spokes, rings, or other supporting structures. In oneembodiment, air passages are provided between a leg attachment and aninner ring via the indentations, such as indentation 1524. Again, theplastic welds, such as plastic weld 1542, provide additional structuralrigidity and strength to the base 102 of exercise step 100, and otherbase portions of other embodiments disclosed herein. In addition, thespokes and rings and lip 1540 that are formed, by way of theindentations, such as indentation 1524 (FIG. 15), also add additionalstrength to the base of the exercise step, such as base 102 of exercisestep 100, disclosed in FIG. 1, and other embodiments disclosed herein.The structural rigidity provided by the plastic welds and the spokes,rings and lip reduces the amount of plastic that is used in the base ofthe exercise step and reduces the overall cost of the exercise step,while still providing the same strength and rigidity.

FIG. 17 is a sectional view of an injection mold 1700 for anair-cushioning leg. As shown in FIG. 17, there are several outer moldpieces, i.e., outer side mold 1702, outer side mold 1704, outer uppermold 1714, outer upper mold 1716 and outer lower mold 1718. These outermolds surround the exterior portion of the molded piece 1712. An innerrotating mold 1706 is disposed in the interior portion of the outermolds 1702, 1704, 1714, 1716, 1718 and provides a gap between the innerrotating mold 1706 and the outer molds 1702, 1704, 1714, 1716, 1718 toform the molded piece 1712. The interior rotating mold 1706 has a spiralshape, so that the interior rotating mold 1706 can be removed from themolded piece 1712 by twisting the interior rotating mold 1706 in therotational direction 1708, after removal of outer upper molds 1714,1716. In other words, after the molded piece 1712 has cooled to acertain extent, and while the outer side molds 1702, 1704 and outerlower mold 1718 are in place and the outer upper molds 1714, 1716 havebeen removed, the inner rotating mold 1706 can be carefully rotated toremove the rotating interior mold 1706 out of the molded piece 1712. Inthat regard, the outer side molds 1702, 1704 and outer lower mold 1718may be released to some extent to reduce some of the pressure created onthe molded piece 1712, so that the interior rotating mold 1706 can bemore easily removed. In addition, injection openings 1720, 1722 provideopenings to insert the heated plastic under pressure into the injectionmold 1700 to form the molded piece 1712.

FIG. 18 is a schematic perspective view of a flow regulator 1800. Asshown in FIG. 18, the flow regulator 1800 has a frame 1802 with arecessed portion 1804. The recessed portion 1804 is recessed to engagean opening that comprises the flow regulator opening, such as flowregulators 1456-1462 that have an opening in the lower plate 408 of base402, as illustrated in FIG. 6, and the other embodiments disclosedherein. Additionally, the flow regulator 1800, illustrated in FIG. 18,can also function as a central control regulator, such as centralcontrol regulator 464, illustrated in FIG. 6, and other embodimentsdisclosed herein. The flow regulator 1800 has a porous insert 1806 thatcontrols the flow of air through the flow regulator 1800 and alsoreduces noise of air that flows through the flow regulator 1800. Theporosity of the porous insert 1806 controls the rate of flow of airthrough the flow regulator 1800 for any given air pressure differentialbetween interior portions of the base of the exercise step and the outeratmosphere.

FIG. 19 is a schematic diagram of an embodiment of an air controlregulator 1900. As shown in FIG. 19, a slide cover 1904 is mounted in aslide 1908. Slide cover 1904 has a handle 1906, which allows themovement of slide cover 1904 on the slide 1908. The slide cover 1904 canbe moved to adjust the size of the opening 1902. In addition, a porousmaterial, such as a foam, can be mounted in the opening 1902 to reducenoise of air flow through the opening 1902. The air control regulator1900 can be disposed in the center of the bottom plate. The air controlregulator 1900 can also be used as a flow regulator in the legattachments to control the flow of air from each of the air-cushioninglegs.

The foregoing description of the invention has been presented forpurposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise form disclosed, andother modifications and variations may be possible in light of the aboveteachings. The embodiment was chosen and described in order to bestexplain the principles of the invention and its practical application tothereby enable others skilled in the art to best utilize the inventionin various embodiments and various modifications as are suited to theparticular use contemplated. It is intended that the appended claims beconstrued to include other alternative embodiments of the inventionexcept insofar as limited by the prior art.

What is claimed is:
 1. A method of making an exercise step comprising:forming a plurality of clockwise air-cushioning legs comprising: forminga first sidewall having a clockwise spirally shaped bulge that allowssaid clockwise air-cushioning leg to compress when a user steps ontosaid exercise step; attaching a first non-slip cover to a bottom portionof said first sidewall to form an airtight seal with said bottom portionof said first sidewall; forming a first attachment plate that isconnected to an upper portion of said first sidewall having latches forattaching said clockwise air-cushioning legs to said exercise step;forming a plurality of counterclockwise air-cushioning legs comprising:forming a second sidewall having a counterclockwise spirally shapedbulge that allows said counterclockwise air-cushioning leg to compresswhen a user steps onto said exercise step; attaching a second non-slipcover to a bottom portion of said second sidewall to form an airtightseal with said bottom portion of said second sidewall; forming a secondattachment plate that is connected to an upper portion of said secondsidewall having latches for attaching said counterclockwiseair-cushioning legs to said exercise step; forming a base comprising:forming an upper plate from a parison in a blow molding process; forminga lower plate from said parison in said flow molding process comprising:forming a plurality of curved rings in said lower plate that providecircumferential support to said lower plate; forming a plurality ofspokes in said lower plate that inter-connect said plurality of curvedrings to provide lateral support to said lower plate, said plurality ofspokes also providing a plurality of air flow passages; forming legattachments in said lower plate that allow said latches on said firstattachment plate and said second attachment plate to connect saidair-cushioning legs to said lower plate with a substantially airtightseal; placing adjustable flow regulators on a first set of openings insaid leg attachments that allow air in said clockwise air-cushioninglegs and said counterclockwise air-cushioning legs, that is compressedwhen said user steps onto said exercise step, to be individually andseparately controlled from said clockwise and counterclockwise aircushioning legs through said first set of openings in said legattachments; placing an air control regulator in said lower plate thatis communicatively coupled to said air flow passages that collectivelycontrols air flow from said air flow passages; welding recessed portionsof said lower plate to said upper plate to strengthen and form said airpassages in said spokes; regulating air flow in said first set ofopenings and said second opening to control the rate of flow of saidcompressed air from said clockwise air-cushioning legs and saidcounterclockwise air-cushioning legs using said adjustable flowregulators and said air control regulator.
 2. A method of forming aspirally shaped air-cushioning leg comprising: providing an exteriormold having a spirally shaped leg portion for injection molding of saidair-cushioning leg having a spiral shape; providing an interior moldthat has a spiral shape; injecting a thermoplastic material between saidexterior mold and said interior mold in an injection molding device toform an air-cushioning leg molded piece; unscrewing said interior moldfrom said air-cushioning leg molded piece formed between said exteriormold and said interior mold after said air-cushioning leg molded piecehas cooled sufficiently to allow said interior mold to be removed;releasing said exterior mold to remove said spirally shapedair-cushioning leg.